Cableway for bridge construction



1964 .LA. PARK ETAL CABLEWAY FOR BRIDGE CONSTRUCTION Filed Aug. 28, 19625 Sheets-Sheet 1 b ///M//HV 1 r wv m3 R INVENTORS J/nv 19. Park ByPose-27' 7? Fox MW...

Jan. 7, 1964 J. A. PARK ETAL CABLEWAY FOR BRIDGE CONSTRUCTION 5SheetsSheet 2 Filed Aug. 28, 1962 INVENTORS J20 4. PJRK BY P7' 7-? FoxMWms m 5 Sheets-Sheet 3 J. A. PARK ETAL fram/ar Jan. 7, 1964 CABLEWAYFOR BRIDGE CONSTRUCTION Filed Aug. 28, 1962 J. A. PARK ETAL 3, ,838

CABLEWAY FOR BRIDGE CONSTRUCTION 5 Sheets-Sheet 4 Arm/giver:

Jan. 7, 1964 Filed Aug. 28, 1962 0 P m mm n a MA 72 2 l 2 3 M N l I #RW1 a M o lo 9 1K I I] 2 4, 78 H 7 U 2 H I 1 4 n 8 .V z: m 2G1 H z I "-1"y 7 w mm I I #1 a \w u 2 I a 9 I L A m a n E 1| LW| H.. o I QU w 0 O m 2l\ O o o 1 FIE! lU United States Patent 3,116,838 CABLEWAY FOR BRIDGECONSTRUCTION John A. Park, P.0. Box 1532, Pueblo, 0010., and Robert P.Fox, St. Paul, Minn.; said Fox assignor to American Hoist & DerrickCompany, St. Paul, Minn, a corporation of Delaware Filed Aug. 28, 1962,Ser. No. 220,592 13 Claims. (Cl. 21294) The present invention relates tocableways and more particularly to a cableway which may be used in theconstruction of bridges, dams or other structures across deep canyons orin normally inaccessible places.

Normally in bridge construction across canyons or deep gulleysparticularly, the bridge piers are built and the girders for the bridgeare placed on top of the piers from the ground surface. A great amountof false frame work has to be built to support the girders as well asthe piers during the bridge building operation. Cable- Ways eliminatethis falsework, and permit fast construction work in rough terrain.

The device of the present invent-ion presents a cableway which ismounted to two towers, placed on opposite sides of a canyon. The trolleyfor carrying the work or load hook is mounted on a two-part track cableas shown, so that very high loads can be carried with the trolley. Inaddition the towers are pivotally mounted about two axes, about a firstaxis so that the tower may be raised into working position and about asecond axis for moving the top of the tower from side to sidesufiiciently far so that girders for opposite sides of a road bed can beput into place without changing the position of the towers. The amountthe towers tilt can be changed to meet any requirement.

The unique two part track cable permits extremely high loads to becarried and thus facilitates the bridge construction by lowering costand speeding up the overall operation.

Carriers are provided for the trolley control lines to support the slackportions as the trolley moves from side to side between the towers.Also, a unique construction of the tower is utilized for placing thetrack cables over sheaves at the top of the tower.

All of the cables can be a standard length as takeup reels are providedfor storage of excess cable beyond any dead end points of the device.

It is an object of the present invention to present a new and improvedcableway construction for building bridges dams and other structures innormally inaccessible areas.

in the drawings,

FIG. 1 is a schematic side elevational view of a cableway made accordingto the present invention;

FIG. 2 is a schematic end elevational View of a tower used in the deviceof FIG. 1;

FIG. 3 is a schematic view taken as on line 3-3 in H6. 2;

FIG. 4 is an enlarged side elevational view of a cableway tower used inthe device made according to the present invention;

FIG. 5 is an enlarged end elevational view of upper sheaves on the cabletower of FIG. 4;

FIG. 6 is a fragmentary enlarged side elevational view of lower supportson a trolley used in the device of the present invention;

FTG. 7 is a fragmentary enlarged side elevational view of a latchmechanism used to engage and move a trolley control line carrier in thepresent invention;

FlG. 8 is an enlarged fragmentary perspective View of a base of a towerused in the device of the present invention;

3,116,838 Patented Jan. 7, 1964 FIG. 9 is a top plan view of a cablewinch used for operating the trolley of the present invention;

FIG. 10 is a perspective end view of the device of FIG. 9;

FIG. 11 is a fragmentary enlarged schematic view of the trolley and ropecarriers;

FIG. 12 is a schematic view of mechanism used to erect the towers; and

FIG. 13 is a schematic view of a modified form of backstay and trackcable anchoring mechanism.

Referring to the drawings and the numerals of reference thereon, acableway illustrated generally at 19 includes a first end tower 2t} anda second end tower 21, each of which is pivotally mounted about twoseparate axes, as shown in FIG. 8, on pins 22 and 23, to a base 24 whichis very firmly anchored into the ground surface illustrated at 25. Thetowers are suitably anchored to the ground surface 25 with backstays 26,26 which are anchored to the ground as at 27. As shown schematically inFIG. 1, one backstay is used. However, in actual operation, a pluralityof backstays can be used if necessary.

A trolley or trolley car 30 is illustrated schematically in FIGS. 1 and4 and fragmentarily in FIG. 6. The construction of the trolley will bemore fully explained later. The trolley is carried on a plurality ofsheaves shown generally at 31, which engage two track cable lengths 29and 32, which are part of one long track cable 33. The track cable notin use is wound onto a storage drum illustrated schematically at 34. Onelength 01f the track cable passes through a first line clamp 35 which isfirmly anchored into the ground 25 and then extends upwardly at an angleover a first track cable sheave 36 which is rotatably mounted withrespect to first tower 29. The lower cable length 32 extends between thetowers above the work site and is mounted over a second trolley cablesheave 37 on sec/0nd tower 21. The track cable then extends downwardlyto a third track cable sheave or tail block 40 which is rotatablymounted as at 41 to a support 42 which is firmly anchored into theground. The track cable 33 is then extended upwardly over a fourth trackcable sheave 43 which is rotatably mounted with respect to the secondtower 21. and cable length 29 extends back to the first tower 21) aboveand substantially parallel to the lower length 32 of the cable.

The cable is then mounted over a fifth track cable sheave 44 which inturn is rotatably mounted with respect to first tower 28. The cable thenextends downwardly back to the ground as at 4-5 and is anchored to aline clamp 46 which in turn is firmly anchored to the ground.

The excess cable is then stored on storage reel 34.

It can be seen that the two lengths of track line 33 are connectedtogether through sheave 40 so that any load on one of the lengthsextending between the towers will be transmitted through the sheave 40to the other part of the line. Thus the load is always equalized betweenthe cable lengths and a great deal more load can be lifted by thetrolley than with a single part line.

A button line 5t) is used to support rope carriers 60 and 61. The buttonline is dead ended to ground to a suitable clamp 51 and extends upwardlyin a length 52 over a first button line sheave 53 and has a horizontallength 54 which extends between first and second towers 249 and 2.1 andis substantially parallel to the lengths 29 and 32 of the track cable.The button line 50 further is threaded over a second button line sheave55 which is rotatably mounted on second tower 21 and a length 56 of thebutton extends back down to a clamp 57 which is anchored in the ground25.

The button line is used to support first and second rope carriers 60 and61 respectively. Rope carrier stops 62 and 63 are provided on the buttonline and prevent the rope carriers from moving toward the center of thecable assembly past their stops. The rope carriers 60 and 61 are furthersupported on a plurality of sheaves 64 and 65, respectively, which rideon upper length 29 of the track cable. The rope carriers are utilized tosupport the trolley control cables.

These supports and the trolley controls will be more fully explainedlater.

In addition, a messenger line 68 is provided. The messenger line isthreaded over a first sheave 69 on first tower 20 and a second sheave 70on second tower 21. The messenger line extends downwardly as shown as 71and 72 and is dead ended at the base of the towers. The messenger linecarries an electric cable for supplying power to power drums on theremote side of the cable length. A remote side, as shown in FIG. 1, isindicated at 73. The control and work side is indicated at 74.

The trolley or trolley car 30 is constructed, as perhaps best shown inFIG. 6, with a frame 79 which consists of a pair of spaced upright firstend members 80 and 81 respectively and a second pair of spaced uprightend members 82 and 83 respectively. The first and second upright endmembers are joined together at the bottom thereof by a pair of spacedparallel lower frame members 84 and 85 and also are joined together bycrossed braces illustrated generally at 86.

A first upper sheave carrier 89 is pivotally mounted as at 90 betweenthe first upright end members 80 and 81. The sheave carrier 89 has apair of spaced apart sheaves 91 and 92 rotatably mounted thereon. Thesheaves 91 and 92 engage upper length 29 of the track cable.

A second upper sheave carrier 95 is pivotally mounted as at 96 betweensecond upright end members 82 and 83. The second upper sheave carrierhas sheaves 97 and 98 rotatably mounted thereon. Sheaves 97 and 98 alsoengage upper length 29 of the track cable.

A first lower sheave carrier 99 is pivotally mounted as at 100 betweenthe first upright end members 80 and 81 of the trolley and sheaves 101and 102 are rotatably mounted thereto. A second lower sheave carrier 103is pivotally mounted as at 104 between the second upright end members 82and 83 of the trolley and this sheave carrier has sheaves 105 and 106rotatably mounted thereto.

Sheaves 101 and 102 and 105 and 106 engage lower length 32 of the trackcable and the load on the trolley 30 is then supported through thesheaves 91, 92, 97, 98, 101, 102, 105 and 106.

Three load hook sheaves 109, 110 and 111 are rotatably mounted betweenlower frame members 84 and 85, respectively as 112, 113 and 114,respectively. In addition, a small guide sheave 115 is rotatably mountedbetween two center support members 116 and 117.

As shown in FIG. 6, first rope carrier 60 is constructed with twospaced, upper side members 119 and 120. The two rope carriers 60 and 61are substantially the same in construction except one operates to theleft and one to the right.

A button line sheave 122 is rotatably mounted between the side members120 and 119 and is supported on the horizontal length 54 of the buttonline 50 which extends between the two end towers.

The plurality of sheaves 64 are rotatably mounted between sheave sideplates 123 and are supported by and rotate on upper length 29 of trackcable 33. A lower rope carrier sheave 121 prevents the carrier fromjumping off its supporting cables.

A bumper support 124 is fixedly attached between side members 119 and120 and extends toward the trolley 30. A bumper 125 is fixedly attachedto an outer end thereof. A bumper 126 is attached to the side plates123.

The sheave carriers on the trolley also have bumpers 127 and 128 whichare alined with the bumpers on the rope carriers. When the trolley movesinto engagement with the rope carriers the bumpers take the initialshock of contact. In addition, a trolley return line sheave 130 isrotatably mounted between the side support members 119 and 120, atrolley line guide sheave 131 and a trolley control line guide sheave132 are also rotatably mounted between the side members.

A pair of latch assemblies illustrated generally at 135 are provided atthe upper ends of the pairs of upright side support members of thetrolley. The latch assemblies are utilized for engaging the respectivealined and adjoining rope carriers and moving the rope carriers with thetrolley as the trolley goes back and forth between the towers. The latchassemblies will permit the rope carriers to be returned against thestops 62 and 63, respectively, when the trolley is returned toward thecenter of the cable support from position adjacent either tower.

The latch assembly consists of a latch dog 136 which is pivotallymounted as at 134 to the upper ends of the upright support members 80and 81 and 82 and 83 respectively. The latch dogs 136 extend outwardlyin a direction parallel to the track cables beyond the bumpers on thetrolley.

As can be seen the outwardly extending ends 137 of each of the latchdogs has a tapered ramp 138 and a cam receptacle 139 which is positionedto engage a roller 140 that in turn is rotatably mounted on a support141 which is fixedly attached to sheave side plate 123. The roller 149is rotatably mounted with respect to the rope carriers. As statedpreviously each of the rope carriers is substantially identical inconstruction and there is a roller 140 which will be engaged by theopposite latch member on the trolley as the trolley moves towardopposite towers from center.

As can be seen best in FIG. 7 the latch dog 136 is guided with uprightguide members 145 which are fixedly attached to a bracket 146 which inturn is fixed to the upper sheave carriers on the trolley. A rod 147 isslidably mounted with respect to bracket 146 and a spring 148 ispositioned beneath the bracket and around the rod 147. A clevis 149 isattached to the rod 147 and also is attached to an ear 150 on the latchdog 136. A washer 151 is positioned over rod 147 and abuts on lower endof the spring. A pair of nuts 152 are threadably mounted on the rod andare used to adjust tension on the spring 148.

The spring 148 exerts a resilient force downwardly in the direction asindicated in arrow 155 in FIG. 7 and thus insures that the camreceptacle 139 will be nested on the roller 140 when they engage. Thespring 149 will yield to permit the latch dog 136 to pivot upwardly asthe roller engages and moves along surface 138.

As can be seen, when the trolley moves in the direction as indicated byarrow 156 in FIG. 1, and with the rope carrier against stop 62 on buttonline 50, as the trolley 30 approaches the rope carrier 60 the outer end137 of latch dog 136 will engage roller 140 and the roller moves alongsurface 138. This will lift the latch member up over the roller and whenthe cam receptacle 139 has traveled far enough it will snap over andlock onto roller 140. The bumpers 125 and 126 of the rope carrier andthe bumpers 127 and 128 on the trolley will collide and the trolley willpush the rope carrier along.

When the trolley is moved in an opposite direction from arrow 156, thecam 139 will engage roller 140 and the rope carrier 60 will be pulledalong with the trolley until it engages stop 62. The latch dog 136 willmove upwardly in direction opposite from that shown by arrow 155 and therope carrier will be released. The same action will occur when thetrolley moves against the second rope carrier 61.

It should be noted that button line is the same length as the workinglengths of the track cable. Thus thermal expansion and working strainsof the two cables will be identical and the button line will not becometoo loose or too slack for the rope carriers to function.

The trolley is moved through the utilization of a trolley control cableor line 160. The trolley control cable 160 is controlled with a tractiondrum 195 illustrated in FIG. 9. As shown there the trolley control cable160 is endless and wound about the drum 159. As shown schematically inFIG. 1, a first length 161 leading from the drum eX- tends under a guidesheave 162 rotatably mounted in a sheave block 163 (FIG. 8), which isattached to the base 24 of the tower on the work side 74 of thecableway. The in haul portion of the trolley cable then has an upwardlyextending length 164 and is mounted on a second trolley control sheave165 which is rotatably mounted with respect to first tower 20. Thetrolley cable has a second length 166 which extends toward the trolleyand is mounted over a trolley sheave 167 which is rotatably mounted withrespect to the trolley as at 163. The trolley cable then has a thirdlength 171 extending back over tower 20 where it is mounted over asheave 172, which is rotatably mounted with respect to the tower 21). Adownwardly extending length 173 is then mounted over a sheave 174 whichin turn is rotatably mounted in a sheave block at the base of the tower20. The in haul part of the trolley control cable is then dead ended asshown at 175. Excess cable is wound on a storage reel 176.

The return portion of the trolley cable extends from the traction orcontrol drum 159 and has a first length 189 which extends to a firstreturn sheave 181 mounted in a sheave block 132 and has a second returnlength 133 extending upwardly to be threaded over a sheave 184 rotatablymounted on tower 2h. The return portion of the trolley control cablethen has a third horizontal length 185 which is threaded underneathsheave 130 on first rope carrier 61) and is then threaded over sheave115 on trolley 30 and is then threaded over sheave 1313 of second ropecarrier 61. V

The return portion cable 160 is then mounted over a sheave 186 which isrotatably mounted with respect to tower 21. A fourth horizontal length 137 of the return portion of the control cable then extends back totrolley 30 and is mounted over a sheave 188 which is rotatably mountedas at 189 to an opposite end of trolley 30 from sheave 167. A fifthlength 190 of the trolley return cable then extends back to tower 21 andis dead ended on the tower.

Thus it can be seen that by operating drum 159 the trolley will be movedbetween the towers in one direction or the other. Because the cable isendless there is no need for any takeup drums on either side of thecable as what is paid out from one side of the drum is automaticallytaken up by the other. This makes a very smooth operation of thetrolley. The drum construction will be more fully explained later.

A load line 195 is mounted over and driven from a load drum 196 and isfurther mounted over a sheave 197. The load line has an upwardlyextending length 198 which in turn is mounted over a second sheave 199which is rotatably mounted on tower 20. The load line then extendshorizontally underneath roller or sheave 131 on first rope carrier 60and is rotatably mounted over sheave 109 on the trolley. The load linehas a load lifting portion 2% extending downwardly from sheave 109 whichin turn is mounted over a sheave 201 that is rotatably mounted onto aload spreader block or hoist hook assembly 202. The hook assembly alsohas a second sheave 203 rotatably mounted thereon and the line ismounted underneath the sheave. An upwardly extending portion 204 is thenmounted over sheave 111 on carrier 30 and the load line then extends toa sheave 207 which is rotatably mounted on second tower 21. The linefurther extends downwardly to be mounted over a sheave 26-3 which isrotatably mounted with respect to the ground 6 and is dead ended as at209 on the ground. A storage reel 210 is provided for taking up anyexcess line.

If desired the load line can be reeved as shown in dotted lines in FIGS.1 and 11, so that two additional working parts 211, 211 will beeffective in raising the load. In doing this the load line is threadedfrom sheave 210 upwardly over sheave on carrier 30 and then downwardly.It is then mounted on sheave 203. This increases the lifting capacity ofthe cable used for the load hook 2112. The load line runs through itssheaves as the trolley moves. The load hook can be raised or loweredsimultaneously with movement of the trolley.

In FIG. 2 is mechanism utilized for moving each of the towers 2t} and 21from side to side. As can be seen the tower is pivoted with respect tothe base 24 about axis pin 22.

As shown by way of example, the top of the tower supporting the trackcable 33 can be tilted 20 feet to the left or right of center. Thepositions of the tower are shown in dotted lines in FIG. 2. Beamscarried by the load hook may be placed 40 feet apart on the bridgepiers. A complete road can then be constructed using only the cableway.

A pair of side guy wire assemblies 215 and 216 are attached to the topof the tower as at 217 and extend backwardly down to the ground. Guywire 215 is attached to the ground as at 218 and the guy wire 216 isattached to the ground as at 219. The guy wires are securely anchoredinto the ground 25.

Each of the guy wires has an upper portion 212 and a lower portion 213and suitable adjustable tackle indicated generally at 226 extendingbetween the upper and lower portions. As shown in FIG. 3 and FIG. 2 aset of lower sheaves 221 is attached to each of the lower portions 213and a set of upper sheaves 222 is attached to each of the upper portions212 of the guy wires. In each of the tackle assemblies, as shown, acable 225 is dead ended as at 226 to a lower sheave block located in guywire 216 and then threaded alternately over sheaves of the upper andlower sheave assemblies and then has a length 227 extending downwardly.The cable extends over a winch drum 228 which is powered with a motor229. The cable extends horizontally as at 231 under a sheave 23 1 whichis fixedly attached to a bracket 232 which is fixed to the ground. Thecable has an upwardly extending length 235 which extends upwardly to afirst sheave of the upper sheave assembly 222 in guy Wire 2115 and thenis threaded between the upper and lower sheaves as before and is deadended to a lower sheave assembly 221 of guy wire 215.

As can be seen the cable 225 is continuous and in order to tilt thetower in either direction the drum 22 8 is activated which will shortenthe center distances between the upper and lower sheave assemblies inone guy wire and will lengthen the center distances between the upperand lower sheaves of the opposite guy wire.

It can be seen that the tilting of the tower from side to side isaccurately controlled and the tower is firmly held at all times duringthis operation. The tower will continue to support the necessary cablesduring this moving operation.

In FIGS. 4 and 5 there is shown structure utilized in placing the trackcables for the trolley into place at the top of the tower as well asother cables that are necessary for operation of the unit. As can beseen the sheaves 44 and 36, which are used to support the track cable attower 20 are rotatably mounted on sheave pins 241) and 241 respectivelywhich in turn are held on suitable support members 242 of the tower.

The sheaves can be removed from their provided slot 243 defined by thesupport members 242, 242.

A lifting jib 244 is provided at the very top of the tower. The jibsupports a pair of jib sheaves 245 and 246 which are rotatably mountedto the lifting jib at the outer ends thereof. The jib sheaves 245 and246 are spaced an equal distance from the center of the tower. Thelifting jib 24-4 is rotatably supported with suitable members 247extending upwardly from support members 242, 242. The jib 244 isrotatably mounted about a vertical axis. A cable 250 is mounted on awinch drum 255 which is driven by a motor 256 and extends upwardly in alength 254 and is then threaded over jib sheave 246 and extends acrossthe top of the jib and over sheave 245. The cable has a length 252extending downwardly. A lifting hook 253 is attached to the end of thecable. The winch and lifting jib are used for hoisting the track cable33 into place over the sheaves on the towers. As can be seen the cable33 is hoisted upwardly. The upper sheave 44 is removed from the tower bypulling pin 240. The track cable 33 is then slipped through an opening266* which is open to slot 243 by rotating the jib until the track cableis properly positioned and is then placed over the lower sheave 36. Thesecond cable length is placed in position the same way after the sheave44 has been replaced so it is rotatably mounted on pin 240. The liftinghook raises the cable upwardly and the cable is slipped through opening260. A platform 261 is provided adjacent the upper portions of the towerfor people to stand on to help move the cable in place.

As can be seen the jib extends outwardly from the sides of the tower anequal distance and thus the loads on the top portions of the tower areequalized. No bending moment is introduced into the lifting operation.The upper portions of the tower, of course, are highly susceptible tobending loads and damage to the tower could result from any heavybending loads. By having an equalized load the upper portions of thetower can be much lighter than if a cantilevered jib was used. Rotatingthe jib about its axis makes it easy for the track cable to be installedthrough opening 260 onto the track cable sheaves.

Thus through the use of this type of assembly the installation of thetrack cable is greatly simplified and the upper portions of the tower donot have to be specially reinforced.

Referring to FIG. 9 the driving winch assembly for the trolley controlcable is shown. An electric motor 263 is mounted on a winch base 264which can be permanently mounted to asupport such as a floor of asemitrailer positioned on the work side of the cableway. The motordrives through a suitable drive arrangement 265 to a jack shaft 266which in turn is drivably connected to a drive arrangement 267 whichdrives a drum shaft 268. The trolley control drum 159 is drivablymounted on the drum shaft 268. The trolley control cable 160 is mountedover provided grooves in the drum. As shown the first length 161 of thetrolley control cable 160 is placed in a first groove 271 of the drum.Also as shown in FIGS. 9 and 10 an idler sheave 272 having a pluralityof grooves is mounted on a shaft 273 which in turn is rotatably mountedin suitable bearings 274 mounted to the base frame 264 of the winch.

As can perhaps best be seen in FIG. 10 the axis for the sheaves 272 ispositioned at an angle with respect to the axis of drum 159.

In this position, the lower portion of a first sheave groove 275 isalined to receive a cable length coming from first groove 271 of thedrum. The first sheave groove 275 then directs the cable to a seconddrum groove 276. A second sheave groove 277 receives 21 cable from theunderside of second drum groove 276 and directs the cable to position ina third drum groove 278. The cable is then received by a third sheavegroove 279 which is directed to the fourth or last drum groove 280. Theopposite lengths of the trolley cable then leaves the control drum fromthe fourth groove 280.

By wrapping the cable around the drum several times, as shown in FIGS. 9and 10, the load which can be moved by the drum is greatly increased.The angled sheaves insure that the cable will lead into the propergrooves on the drum at all times.

As shown schematicall in FIG. 12, when the towers 29 or 21 are to beraised, they are assembled in a horizontal position with pin 23installed in base 24. A strut 285 is pivotally mounted as at 284 on thebase also. The strut has a saddle 286 at the top thereof. Backstay 26,which is attached to upper portions of the tower is placed on saddle 286and attached to tackle mechanism 187 operated by a winch 289. Inaddition, a guy wire 289 is attached between the strut 285 and thetower. The tower is then pivoted to upright position by pulling onbackstay 26.

The strut increases the moment which can be placed on the tower to tendto lift it into upright position. Once the tower is in place, thebackstay is anchored and the strut can be removed. When both towers arein place the cables extending between the towers can be installed.

The use of the cableway makes bridge construction very easy. Theconcrete for the piers can be carried to the forms in suitablecontainers. The operation is simple and rapid. Deep canyons present noproblem.

If greater loads are to be lifted a track cable of more than twosupporting lengths can be used. The tail block sheave 40 acts as a loadequalizing sheave. Other load equalizing sheaves would be added if morelengths are used for support.

All power generators and the control cable drum can be mounted in a semitrailer for easy moving of the equipment.

The tilting feature of the towers permits building a road bed with thecableway without moving the tower foundations. This makes the use ofcableways feasible for construction jobs.

It has been found that in very rough terrain it is not always possibleto anchor the backstay of the tower along the tilting axis of the tower.If the anchor points are not on this axis as the tower tilts the trackcables and backstay will tighten or loosen, depending upon the positionthereof.

Where the tilting of the tower is minimal this does not become aproblem. However in some construction jobs it is necessary to cover awide area with the cableway. For example, using a 200 foot tower, thetop of the tower may be tilted feet to either side of center. Anymisalinernent between the anchor points and the tilting axis becomessignificant.

Also in very rough terrain the anchor points may be on the side of ahill and vertically offset from the tower axis a considerable distance.

In FIG. 13 structure is shown which will compensate for the differencesin length of the track cable and the backstay which are necessary tohold the towers properly positioned under these conditions.

As shown, the backstay 26 and the two lengths of track cable 33 whichare normally anchored to the ground will be fastened with respect to asheave block 291. The backstay is fastened directly thereto, as at 292.The track cable is passed through clamps 293, 293, which are the same asthe clamps 35 and 46 used previously at the ground. The clamps are ofdesign so that the cable is not kinked or damaged. The excess cable isstored on storage drums 34, 34 as before.

The clamps 293, 293 are attached to the sheave block as at 294, 294. Asheave 295 is rotatably mounted in the sheave block 291.

An adjustment cable 296 is anchored to ground 25 with a double swivel227. The adjustment cable 297 extends over sheave 295 and an upperadjustment sheave assembly 298 is rotatably attached with respect to theother end of the cable.

A lower adjustment sheave assembly 301 is rotatably tounted in a doubleswivel block 362 which in turn is attached to the ground at positionspaced from double swivel 297. A cable 303 is reeved between the .upperand lower sheave assemblies 298 and 301 respectively.

An end portion 304 of cable 303 extends from the lower sheave assemblyto a suitable conventional power hoist 305.

By controlling the cable 303 to lengthen or shorten the distance betweenthe upper and lower adjustment sheave assemblies, the length of thetrack cable and backstay can be accurately controlled to compensate fornecessary changes when the tower is tilted. .It can :be seen that thesame adjustable machinery can be used for mounting the backstay andequalizing sheave for the track cable on the .remoteside of thecableway.

Because the towers can be tilted a great amount to either side, and, ofcourse, can be positioned any desired distance apart, a large area canbe covered for construction work without changing the tower positions.Regions formerly completely inaccessible now can be worked forconstruction of dams, bridges or other structures.

While the description herein deals mainly with a cableway for bridgeconstruction, it is to be considered by way of example rather thanlimitation. It is apparent that the cableway can be adapted to manyconstruction projects.

What is claimed is:

l. A cableway comprising a pair of spaced apart towers, a track cablesuspended between said towers, a trolley mounted for movement along saidtrack cable, cable means for moving said trolley back and forth betweensaid towers, said cable means for moving said trolley being controllablefrom position adjacent a first of said towers, a load line carried bysaid trolley having means thereon to support a load, means adjacent afirst of said towers to control said load line and thereby raise andlower a load carried by said trolley, a button line extending betweenand supported by said towers, at least one rope carrier supported by andmovable along said button line, said rope carrier having means thereonto support said cable means for moving said trolley, said track cablebeing anchored at a first end thereof with respect to the ground atposition spaced from said first tower, extending over a first sheaverotatably mounted on said first tower, thence extending over a sheaverotatably mounted on said second tower, thence extending over a sheaverotatably mounted with respect to, supported by and adjacent the ground,thence extending back over a fourth sheave rotatably mounted on saidsecond tower spaced from said second sheave, thence extending over afifth sheave rotatably mounted on said first tower, and clamp meansanchored with respect to the ground adjacent the first end of said cablefor receiving said cable from said fifth sheave.

2. The combination as specified in claim 1 wherein said track cable isof standard length and excess cable is stored on a storage drumrotatably mounted adjacent said clamp means.

3. The combination as specified in claim 1 wherein said trolley hassheaves mounted thereon that engage said track cable so that each of theportions of said cable extending between said towers supports an equalload.

4. A cableway comprising a pair of spaced apart towers, two lengths oftrack cable suspended between said towers, said track cable lengthsbeing joined together and mounted over a rotatable load equalizingsheave, a trolley mounted for movement along said track cables andhaving means thereon for transferring load to both of said cablelengths, power operated continuous cable means for moving said trolleyback and forth between said towers, a button line extending between saidtowers and fastened with respect thereto, a rope carrier mounted formovement along said button line, said trolley controlling movement ofsaid rope carrier, means on said rope carrier for supporting said cablemeans, a load line carried by said trolley and extending to at least one.of said towers, said load line having means thereon to .engage andsupport a load, and means adjacent a first of said towers to controlsaid load line and thereby raise and lower a'loadcarried by saidtrolley.

5. The combination as specified in claim 4 wherein .said button line isthe same length as said track cables.

6. The combination as specified in claim 4 wherein 7. The combination asspecified in claim 6 wherein said track cable lengths are verticallyspaced and each length is mounted over a separate sheave at each tower,said load equalizing sheave being mounted adjacent the ground spacedfrom said second tower and the cable lengths being fastened with respectto the ground at position spaced from said first tower.

8. The combination as specified in claim 7 wherein said track cable,said load line and said button line are of standard length and excesscable is stored on rotatably mounted storage drums.

9. The combination as specified in claim 7 wherein a backstay isfastened to said first tower, and wherein said backstay and said cablelengths adjacent said first tower are attached to a sheave block, andadjustable means connecting said sheave block to the ground.

10. The combination as specified in claim 4 wherein two rope carriersare provided, separate spaced apart stop means on said button line foreach carrier, a first of said rope carriers being movable along saidbutton line be tween said first tower and a first of said stops, asecond of said rope carriers being movable along said button linebetween said second tower and a second of said stops, said trolleyhaving means thereon to engage said first carrier and move it towardsaid first tower as said trolley moves from center portions of saidcable toward said first tower and to move said first rope carrieragainst said first stop as said trolley returns to center, said trolleyalso having means to move said second rope carrier toward said secondtower and to return said carrier to position against said second stopresponsive to movement of said trolley.

11. The combination as specified in claim 10 and a separate jibrotatably mounted on each tower about an axis substantially coincidentwith the longitudinal axis of its respective tower, a separate pair ofjib sheaves rotatably mounted on each of said jibs, the jib sheave ofeach pair being equally spaced from the axis of their respective tower,and a separate hoist cable reeved on each pair of said jib sheaves sothat a load lifted by said hoist cable results in equal load on each ofthe sheaves in a pair.

12. A cableway comprising a pair of spaced apart towers each pivotallymounted at the base thereof about an axis substantially parallel to aline extending between said towers, a track cable suspended between saidtowers having at least two lengths vertically spaced apart and joined atone end by load equalizing means, a trolley mounted for movement alongsaid track cable lengths and having support means engaging both of saidtrack cable lengths, a powered cable control drum, cable means on saiddrum and reeved to said trolley for moving said trolley back and forthbetween said towers, said cable means for moving said trolley beingendless and reeved on said drum so that as cable is payed out from oneside of the drum the slack is taken up by the other side of the drum,and a load line controlled by a winch drum and mounted on a sheave on afirst of said towers, extending to said trolley and being loopeddownwardly to engage and support a sheave on a load hook and extendingfrom said trolley to be dead ended with respect to a second of saidtowers.

13. A cableway comprising apair of spaced apart towers, a track cablesuspended between said towers and having at least two lengths verticallyspaced apart and joined at one end by load equalizing means, a trolleymounted for movement along said track cables and having means thereonfor transferring load to both of said cable lengths, power operatedcontinuous cable means for moving said trolley back and forth betweensaid towers, a button line extending between said towers and fastenedwith respect thereto, a rope carrier mounted for movement along saidbutton line, said trolley controlling movement of said rope carrier,means on said rope carrier for supporting said cable means, a load linecarried by said trolley and extending to at least one of said towers,said load line having means thereon to engage and sup- References Citedin the file of this patent UNITED STATES PATENTS 1,086,912 Hadsel Feb.10, 1914 2,318,218 Grabinski May 4, 1943 10 2,790,622 Priest Apr. 30,1957 FOREIGN PATENTS 843,620v Great Britain Aug. 4, 1960

1. A CABLEWAY COMPRISING A PAIR OF SPACED APART TOWERS, A TRACK CABLESUSPENDED BETWEEN SAID TOWERS, A TROLLEY MOUNTED FOR MOVEMENT ALONG SAIDTRACK CABLE, CABLE MEANS FOR MOVING SAID TROLLEY BACK AND FORTH BETWEENSAID TOWERS, SAID CABLE MEANS FOR MOVING SAID TROLLEY BEING CONTROLLABLEFROM POSITION ADJACENT A FIRST OF SAID TOWERS, A LOAD LINE CARRIED BYSAID TROLLEY HAVING MEANS THEREON TO SUPPORT A LOAD, MEANS ADJACENT AFIRST OF SAID TOWERS TO CONTROL SAID LOAD LINE AND THEREBY RAISE ANDLOWER A LOAD CARRIED BY SAID TROLLEY, A BUTTON LINE EXTENDING BETWEENAND SUPPORTED BY SAID TOWERS, AT LEAST ONE ROPE CARRIER SUPPORTED BY ANDMOVABLE ALONG SAID BUTTON LINE, SAID ROPE CARRIER HAVING MEANS THEREONTO SUPPORT SAID CABLE MEANS FOR MOVING SAID TROLLEY, SAID TRACK CABLEBEING ANCHORED AT A FIRST END THEREOF WITH